采用格林函数分解的太赫兹逆合成孔径雷达近场成像算法

Terahertz Inverse Synthetic Aperture Radar Near-field Imaging Algorithm Using Green's Function Decomposition

针对太赫兹逆合成孔径雷达(ISAR)近场成像的问题,本文提出了采用格林函数分解的ISAR成像算法。文中结合太赫兹雷达超外差接收模式,构建和分析了近场条件下的目标回波模型。通过对回波模型中格林函数的分解,将表征球面波前的格林函数分解为二维平面波的叠加;并在频域完成对回波信号的滤波补偿和二维逆变换后,获得了太赫兹ISAR近场目标的图像。文中通过与二维FFT算法和本文算法进行的数值仿真结果对比,验证了该算法的可行性。最后利用太赫兹雷达转台实测数据对本文算法进行了验证和对比分析,结果表明该算法具有良好的成像性能。

In this paper, an imaging algorithm for terahertz inverse synthetic aperture radar using the Green＇ s function decomposition is proposed to implement near-filed imaging. Combined with the Superheterodyne receiver mode of terahertz radar, the model of terahertz target echo in the near-field is builded and analyzed. The spherical wave which is represented by Green＇ s function is decomposed to the superposition of plane wave components in two dimensions. After completing the operators of the filtering compensation and two dimension inverse fast Fourier transform, the target image of terahertz inverse synthetic aperture radar in the near-field condition. To demonstrate the imaging performances of our method, numerical simulations and experiments are conducted. Comparing the simulation results based on the two dimensional fast Fourier transform method and the proposed algorithm respectively, the feasibility of the proposed algorithm is verified. Finally, the real experimental data are used to validate the performance of the proposed algorithm and the experimental resuhs demon- strate that our method can obtain a good imaging performance.